Pediatric peritoneal dialysis patients may suffer from growth retardation, malnutrition and impaired neurocognitive development. Attempts to address these individual problems have been limited by inconsistent dialysis delivery and the lack of an age-appropriate definition of dialysis adequacy. Proposed is a randomized, prospective, cross-over comparison of usual and intensive peritoneal dialysis, assessing the effect of enhanced small molecule clearance on neuro- cognitive function, growth of lean body mass and dietary protein intake.